diff options
Diffstat (limited to 'arch/x86/kernel/cpu/mshyperv.c')
| -rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index fc6cb84c9fe5..39a4b4509b87 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -32,6 +32,10 @@ #include <asm/nmi.h> #include <clocksource/hyperv_timer.h> +/* Is Linux running as the root partition? */ +bool hv_root_partition; +EXPORT_SYMBOL_GPL(hv_root_partition); + struct ms_hyperv_info ms_hyperv; EXPORT_SYMBOL_GPL(ms_hyperv); @@ -257,6 +261,22 @@ static void __init ms_hyperv_init_platform(void) ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); /* + * Check CPU management privilege. + * + * To mirror what Windows does we should extract CPU management + * features and use the ReservedIdentityBit to detect if Linux is the + * root partition. But that requires negotiating CPU management + * interface (a process to be finalized). + * + * For now, use the privilege flag as the indicator for running as + * root. + */ + if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) { + hv_root_partition = true; + pr_info("Hyper-V: running as root partition\n"); + } + + /* * Extract host information. */ if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= |